Field of the Disclosure
The present disclosure, for example, relates to wireless communication systems, and more particularly to techniques for transmitting channel state information (CSI) based on selected non-frequency domain components of channel responses.
Description of Related Art
Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.
In some examples, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipment (UEs). In a Long-Term Evolution (LTE) or LTE-Advanced (LTE-A) network, a set of one or more base stations may define an eNodeB (eNB). In other examples (e.g., in a next generation or 5G network), a wireless multiple access communication system may include a number of smart radio heads (radio heads (RHs)) in communication with a number of access node controllers (ANCs), where a set of one or more radio heads, in communication with an ANC, defines an eNB. A base station or radio head may communicate with a set of UEs on downlink channels (e.g., for transmissions from a base station or radio head to a UE) and uplink channels (e.g., for transmissions from a UE to a base station or radio head).
Some wireless communication systems may use beamforming and/or multiple input/multiple output (MIMO) beamforming to communicate between a network access device (e.g., an eNB, an ANC, a radio head, or a base station) and a number of UEs. Prior to configuring a precoding matrix for a plurality of channels (e.g., a plurality of downlink channels), a network access device may estimate the plurality of channels. In some examples, the channel estimation may be achieved using reciprocal channel estimation (e.g., estimation of a corresponding plurality of uplink channels). However, in some examples, reciprocal channel estimation may not be possible. In these examples, channel estimation may be based on CSI received from a UE. In extreme bandwidth wireless communication systems (e.g., in next generation or 5G networks), the transmission of a full set of CSI for a plurality of channels may consume significant resources (e.g., bandwidth).